1. Field of the Invention
The present invention relates to an information recording device such as an optical disk device having a recording head such as an optical pickup for recording information on a recording medium such as an optical disk, and also relates to a method of controlling the recording operation of the device and a program for controlling the recording operation of the device.
2. Description of the Related Art
In the case where contents information such as movies and broadcasting programs that involve copyrights information is to be recorded on a recording medium such as an optical disk, the contents information is encrypted so as to prevent unauthorized copying. Various methods and techniques to protect copyrights have been developed. For example, the inherent ID recorded on each optical disk during the optical disk manufacturing process is used to generate an encryption key that is required for encrypting contents information. In this manner, a different encryption key can be generated for each optical disk. The recorded inherent ID is read out from an optical disk, and the encryption key for encrypting contents information is generated. Using the encryption key, the contents information to be recorded is encrypted, and is then recorded on the optical disk. Thus, the data recorded on the optical disk can be protected. Meanwhile, in a reproducing device, the inherent ID is acquired from the optical disk, and a common encryption key is generated, based on key generating information that is stored in the device. Using the common encryption key, the encrypted contents information is decrypted and decoded for reproduction.
By the above described conventional method, however, the region in which an inherent ID is recorded on an optical disk during the manufacturing process is normally a disk management information recording region such as the Lead In area that is preset as an access region at the time of an access to the optical disk. When such an optical disk is loaded into an optical disk device to start a recording operation, the inherent ID might not be read out from the optical disk for some reason. In such a case, the contents information cannot be encrypted. Also, once recorded, the inherent ID cannot be updated or changed, which might cause inconvenience.
In the case where inherent IDs are recorded during the manufacturing process before optical disks are shipped, the product control becomes easier at the factory. However, as a different inherent ID is allocated to each optical disk, more time and costs are required for manufacturing the optical disks. Also, in a case where serial numbers are used as inherent IDs to be recorded on optical disks, same numbers (inherent IDs) are not allocated to optical disks, and it is easy to manage the numbers. In this case, however, the numbers can be easily predicted for unauthorized use. As a result, the copyrights protection might become insufficient.